PCE-BTM 2000A Belt tension gauge

The belt tension meter is an optically measuring maintenance tool for determining the belt tension force. This belt tension meter consists of a display device and a sensor head attached on a semi-flexible gooseneck. The advantage of the gooseneck is that the sensor head can be flexibly positioned. Due to the mobility of the gooseneck, the sensor can measure the strand force even in hard to reach places. The belt tension measuring device measures the belt tension (in Newton) and the belt frequency (in Hz) of the belt in the stationary state.

A small impulse on the belt is sufficient to set the belt vibrating. The belt tension meter measures with the sensor the natural frequency of the belt generated in this way and visualizes it on the display. The belt tension meter can directly determine the actual tension (in Newton / Pound Force) of the belt from the belt frequency combined with the optionally entered belt length and belt mass. However, entering this data is not necessarily required in order to carry out the measurements directly with the belt tension measuring device. The measurement units in the device can be switched between N (SI unit) and pound force (US unit).

The reading is always displayed as the belt frequency in Hz on the belt tension measuring device's display. The intuitive graphic menu is shown on the high-contrast display of the belt tension measuring device in six different languages. Up to 750 data records can be stored in the device's memory. The belt tension measuring device is delivered fully ready to use. The scope of delivery includes the handheld device, the standard sensor with gooseneck, a magnetic holder, batteries, and an operating manual. To increase flexibility during measurement, the following items are optionally available for the belt tension meter: an external sensor head with a spiral cable, a device hard case, a frequency mallet, and a tripod.

The belt tension measuring device can measure the tension of timing belts, ribbed belts, and V-belts. 

Belt tension is an important parameter for the maintenance, installation, setup, and repair of belt drives. Belt tension must be regularly checked throughout the entire operating time and adjusted if necessary to ensure the maximum possible service life of all machine components around the belt. It is very important that the preload force is selected according to the forces to be transmitted.

The main principle here is: the greater the forces to be transmitted and the higher the belt speed during operation, the greater the preload forces that must be selected. At the same time, it is necessary to ensure that the belt tension is not set too high, as this can affect the bearings of the belt drives and increase belt wear, which may cause belt cracks. Conversely, too low belt tension can also cause damage, for example, when teeth skip or the belt slips. Therefore, it is important to determine the belt tension or preload force with a belt tension measuring device. This can help significantly reduce follow-up costs caused by unplanned downtime and stoppages due to bearing damage or defective belts. The use of a belt tension measuring device is thus suitable for applications in industrial production, motor technology, stepper motors, machine and tool construction, as well as maintenance and repair.

Since several forces act on a belt drive, the most important forces on belt drives are named below to understand the significance of the belt tension force. The belt connects a drive pulley with a driven pulley. The drive pulley is powered by a motor which generates torque and transmits it to the drive pulley. The belt transmits this torque as a circumferential force to the driven pulley. The following forces are important.

The circumferential force: The circumferential force corresponds to the effective force to be transmitted by the belt. It depends on the applied engine power and thus on the torque as well as on the engine speed and the pulley diameter. To maintain the balance of forces, the circumferential force causes different forces in the strands of the belt. The difference between the forces in the loaded and unloaded runs corresponds to the circumferential force transmitted to the belt.

The frictional force: The frictional force at the drive pulley ensures that the motor's torque is transmitted via the belt to the driven pulley. At the driven pulley, a usable torque is generated which corresponds to the product of the circumferential force and half the diameter of the driven pulley.

The centrifugal force: The centrifugal force increases with increasing speeds and causes the belt to stretch and thus lose grip. In this case, the centrifugal force acts against the adhesion force.

The pretensioning force: The pretensioning force / span force / belt tension differs under dynamic conditions on the loaded and unloaded span. In static conditions, the belt tension is identical in both runs. In the static state, the pretensioning force must be set so that under dynamic conditions there is sufficient adhesion to the pulleys to ensure power transmission from the belt to the pulley, while also considering the centrifugal forces acting on the belt during operation. However, the belt tension must not be set too high, as this can cause belt damage and/or bearing damage under load. The correct belt tension must be selected specifically for each belt and its application. In most cases, belt manufacturers specify the corresponding belt tension in terms of forces or frequencies. A belt tension meter can then be used to accurately determine the required belt tension after installation and before commissioning a belt drive.

The measurement of the belt tension is always necessary when machines and systems are to be optimally maintained. A belt drive reaches its maximum service life only if it is designed and adjusted for its use. This means that the belt should be tensioned for the specific application optimally and the pulleys – precisely aligned. With the help of the belt tension measuring device, the strand force can be determined exactly when the belt is under stationary conditions.

Long service life and high performance of the equipment and the machines – is the wish-goal of every user, either company or an individual. In many industries, in particular, in various mechanisms, belts are an important and necessary part. The smallest deviations from the standards may lead to serious consequences, like system failure, that is why it is especially important to regularly check the belt tension, since only when this value is absolutely correct and optimal, the best performance may be provided. Not only weaker than necessary tension, but also the tension that exceeds the standards, may cause serious and, which is important, preliminary, degradation of the belt and drop of the performance. This could cause serious machine failures with unplanned downtime and high repairing costs. For example, wrong belt tension in the generator of the car is devastating in both cases and may be dangerous and lead to the complete wear of the mechanisms. Significant costs – is just one of the items in the list of the possible problems that may follow. Even if the belt is not broken, the change in its function does not remain unimportant for the whole system or mechanism, and that is why it is actually one of the priority tasks to keep this issue under control.

This is easy to do with the help of the belt tension meter, which is a small but very useful device that can help the user determine the belt tension in the system to be controlled and thus indicate whether prompt measures should be taken to adjust the tension to the setpoint value.

Testing the tension manually remained in the past long ago, and the best way to determine the tension is to use the device and by means of the calculations get exact data about the belt tension. The vibrations coming from the belt are not only registered by the belt tension meter, the data are processed after they have been received by the optical sensor, and based on the characteristics of the belt (weight, width, length), the final result is calculated and displayed on the lighted screen (in N and Hz).

The range of applications is wide, from individual uses in households (various devices and household equipment) or offices to industrial fields where it can be used for different conveyors, lifting equipment, elevators, the automotive industry, or agricultural machines.

The main advantage of the belt tension meter is not only that it helps to detect faults and prevents failures, it may also be used for checking the correctness of the installation before commissioning. Thus, before the equipment gets started, the check by means of the belt tension meter is a reliable confirmation that the machine will run flawlessly in compliance with the regulations. The data received with the help of the meter may be saved and used as a norm-sample during the regular maintenance checks later.